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Coconino Plateau Groundwater Withdrawal Scenario Report

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Prepared in cooperation with the Arizona Department of Water Resources and Yavapai County Simulation of Groundwater Withdrawal Scenarios for the Redwall-Muav and Coconino Aquifer Systems of Northern and Central Arizona Scientific Investigations Report 2016–5115 U.S. Department of the Interior U.S. Geological Survey COVER Elevated, northwest-looking Google Earth view of Flagstaff, Arizona, in the foreground, the Coconino Plateau in the center, and Grand Canyon in the upper part of the image. Image Landsat from Google (2016). Simulation of Groundwater Withdrawal Scenarios for the Redwall-Muav and Coconino Aquifer Systems of Northern and Central Arizona By D.R. Pool Prepared in cooperation with the Arizona Department of Water Resources and Yavapai County Scientific Investigations Report 2016–5115 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior SALLY JEWELL, Secretary U.S. Geological Survey Suzette M. Kimball, Director U.S. Geological Survey, Reston, Virginia: 2016 For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment—visit http://www.usgs.gov/ or call 1–888–ASK–USGS (1–888–275–8747). For an overview of USGS information products, including maps, imagery, and publications, visit http://store.usgs.gov/. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. Suggested citation: Pool, D.R., 2016, Simulation of groundwater withdrawal scenarios for the Redwall-Muav and Coconino aquifer sys- tems of northern and central Arizona: U.S. Geological Survey Scientific Investigations Report 2016–5115, 38 p., http://dx.doi.org/10.3133/sir20165115. ISSN 2328-0328 (online) iii Contents Abstract ..........................................................................................................................................................1 Introduction.....................................................................................................................................................2 Climate ....................................................................................................................................................2 Vegetation ..............................................................................................................................................4 Land and Water Use .............................................................................................................................4 Regional Hydrogeology .................................................................................................................................4 Aquifer Geology and Structure ...........................................................................................................4 Aquifers .........................................................................................................................................5 Proterozoic Basement .......................................................................................................5 Redwall-Muav Aquifer .......................................................................................................5 Coconino Aquifer ................................................................................................................6 Alluvial Aquifers ..................................................................................................................6 Structure........................................................................................................................................6 Description of the Northern Arizona Regional Groundwater Flow Model ...........................................6 Withdrawal Scenarios ..................................................................................................................................8 Water Uses ..........................................................................................................................................10 Scenario 1 ............................................................................................................................................14 Scenario 2 ............................................................................................................................................14 Scenario 3 ............................................................................................................................................15 Additional Scenario Assumptions ....................................................................................................15 Small Private and Stock Well Withdrawals ...........................................................................15 Natural Recharge Rates ...........................................................................................................16 Incidental Recharge Rates .......................................................................................................16 Drying of Model Cells During the Scenario Simulations .....................................................16 Simulated Effects of Withdrawal Scenarios ...........................................................................................18 Initial Conditions for the Scenarios .................................................................................................18 Scenario Simulation Results .............................................................................................................21 Simulated Changes in Water Levels .......................................................................................21 Scenario 1 ..........................................................................................................................21 Scenarios 2 and 3 .............................................................................................................21 Simulated Changes in Groundwater Discharge ...................................................................25 Scenario 1 ..........................................................................................................................25 Scenarios 2 and 3 .............................................................................................................26 Model Limitations................................................................................................................................27 Summary........................................................................................................................................................28 References ....................................................................................................................................................30 Appendix 1.....................................................................................................................................................33 Appendix 2.....................................................................................................................................................35 Appendix 3.....................................................................................................................................................37 iv Figures 1. Map of the area within the Coconino Plateau Water Advisory Council groundwater with- drawal scenarios ..........................................................................................................................3 2. Conceptualized relations among major hydrogeologic units and the Northern Arizona Regional Groundwater-Flow Model layers...............................................................................7 3. Graphs of projected groundwater withdrawals by major water users for future withdrawal scenarios ........................................................................................................................................9 4. Map of the generalized groundwater-flow system initial conditions ..........................................11 5. Map of water-level change for scenario 1 in the uppermost model layer from 2006 through 2105 near the Coconino Plateau Water Advisory Council scenario region and sur- rounding areas, Arizona ............................................................................................................22 6. Map of the difference in water-level change in the uppermost model layer compared with scenario 1 from 2006 to 2105 near the Coconino Plateau Water Advisory Council Sce- nario region and surrounding areas ........................................................................................23 7. Graph of sources of water, storage or surface-water flow and evapotranspiration, to a pumped well through time .........................................................................................................26 8. Simulated changes in groundwater discharge to major perennial surface water features from 2006 through 2105 in and near the Coconino Plateau Water Advisory Council scenario region ...........................................................................................................................27 Tables 1. Withdrawal wells that were not included in the original Northern Arizona Regional Ground-
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